1. Field of the Invention
The present invention relates to an output impedance matching circuit, and an amplifier having an input impedance matching circuit or an input/output impedance matching circuit, and more particularly, to a multiband output impedance matching circuit having passive devices, an amplifier including a multiband input impedance matching circuit having passive devices, and an amplifier including a multiband input/output impedance matching circuit having passive devices, which can be miniaturized without using a separate output terminal buffer, and reducing current consumption by using passive devices.
2. Description of the Related Art
The recent development of wireless communication technologies is introducing various wireless communication devices in everyday life.
More frequency bands are being used because of the introduction of the various wireless communication devices. Also, as a plurality of wireless communication devices are being applied to real life, a need for convergence of wireless communication devices using different frequency bands has arisen.
The wireless communication device includes a first-stage low-noise amplifier, and a driving amplifier. The first-stage low-noise amplifier receives a wireless communication signal and matches impedance of the received wireless communication signal. The driving amplifier matches impedance of a wireless communication signal, and amplifies and then outputs the wireless communication signal.
The amplifier includes an input/output impedance matching circuit to transmit/receive a wireless communication signal.
However, in order to transmit and receive multiband wireless communication signals, such a related art amplifier includes an input/output impedance matching circuit that uses an active device for choosing multiple frequency bands or a separate circuit for the choosing is additionally adapted, thereby causing the amplifier to increase in size and power consumption.